Table 1.

Summary of recent approaches to glia-to-neuron conversion in vitro and in vivo.

Glial source			Region	Targeted TFs	Small molecules/micro RNA/Others	Neuronal type	Conversion efficiency	Ref.
Mouse	Astrocyte	in vitro (cultured cell)			Forskolin, ISX9, CHIR99021, I-BET151	Glut+/GABA+	High	[49]
			Cortex	NeuroD1		Glut+ neuron	High	[37]
			Cortex	Ngn2	GEND1	GABA+/TH+ cell	High	[50]
			Cerebral cortex	Ngn2		Glut+ neuron	High	[23, 24, 56]
			Cerebral cortex	Pax6		Undefined	?	[21, 23]
			Cerebral cortex	NeuroD4+ Insm1		Glut+ neuron	Low	[56]
			Cerebral cortex	Dlx2		GABA+ neuron	Low	[24]
			Cerebral cortex	Ascl1+ Dlx2		Interneurons	High
			Cerebral cortex	Ascl1		Undefined	Low	[23, 56]
				Ascl1+Lmx1b+Nurr1		Dopaminergic neuron	Low	[25]
			Midbrain	Ascl1+Phox2b+AP−2α+Gata3+Hand2+Nurr1+Phox2a		Noradrenergic neuron	High	[82]
			Dorsal midbrain	Ascl1		Glut+/GABA+	High	[42]
		in vivo	Midbrain	Ascl1		Glut+/GABA+	High	[42]
			Striatum	Ascl1+Lmx1a+ Nurr1		Glut+ (16%)/GABA+ (68%)	?	[39]
			Striatum	Ascl1+Lmx1a+NeuroD1	miR218	Dopaminergic neuron	Low	[41]
			Striatum	Ascl1+Brn2a+Myt1l		Un-defined	Low	[27]
			Striatum		Forskolin+ CHIR99021+ IBET151+ISX9+Y-27632	GABA+ (87.1%)	low	[49]
			Striatum	NeuroD1 + Dlx2		GABA+ neuron	High	[38]
			Striatum	Ngn2	FGF2+EGF	GABA+ neuron	Low	[33]
			Striatum	Sox2		DCX+ cell	?	[28, 29]
			Spinal cord	Sox2	VPA	GABA+ neuron	Low	[30]
			Substantia nigra		PTB/sh RNA	Dopaminergic (30 %)/Others	high	[45]
			Cortex		Forskolin+ CHIR99021+ IBET151+ISX9+Y−27632	Glut+ (72.8%)	Low	[49]
			Cortex	NeuroD1		Undefined	High	[37]
			Cortex	Ngn2	FGF2+EGF	Glut+ neuron	Low	[33]
			Cerebral cortex	Ngn2+Nurr1		Pyramidal neuron	High	[35]
			Cerebral cortex	Ascl1+Nurr1		Undefined	High
			Motor cortex	NeuroD1		Pyramidal neuron(90%)/GABA+ (10%)	High	[36]
	NG 2 cell	in vitro	Cortex	NeuroD1		Glut+ (90%)/GABA+ (10%) neuron	High	[37]
		in vivo	Cortex	NeuroD1		Undefined	High	[37]
			Spinal cord	Sox2		Glut+/GABA+	High	[32]
			Cerebral cortex	Sox2		DCX+ cell	Low	[31]
			Cerebral cortex	Ascl1+ Lmx1a + Nurr1		Glut+ (16%)/GABA+ (68%) neuron	High	[39, 40]
			Striatum		siRNAs 3/4	GABA+ neuron	High	[46]
	Microglia	in vitro		NeuroD1		Glut+ (74.2%) / GABA+ (25.7%)	Low	[56]
		in vivo	Striatum	NeuroD1		Striatal neuron	High	[56]
	Müller glia	in vitro		Ascl1		Bipolar cell	Low	[55]
				Ascl1		Multipolar/uni/bipolar cells	High	[80]
				Ngn2		Unipolar/bipolar cell	High
		in vivo	Injured retina	Ascl1		Bipolar/amacrine cell	?	[43]
			Injured retina	Ascl1	TSA	Bipolar cell	?	[61]
Human	Astrocytes	in vitro	Cortex		LDN193189+ SB431542+ TTNPB+Tzv+ CHIR99021+ VPA+DAPT+ SAG+Purmo	Glut+ (88%)/GABA+ (8.2%) neuron	High	[14]
			Cortex		SB431542+ LDN193189+ CHIR9902+ DAPT	Glut+ (78%)/GABA+ (2%)/Dopaminergic (1%)	High	[48]
			Cortex	NeuroD1		Glut+ neuron	High	[37]
				NeuroD1+Ascl1+ Lmx1a	miR218	Dopaminergic neuron	Low	[41]
	NG2 cell	in vitro		Sox2+Dlx5+Lhx6+ Ascl1+Foxg1	sh REST	GABA+ neuron	high	[84]
				Ascl1+Lmx1a+Nurr1	sh REST	Dopaminergic neuron	?	[85]

TFs transcription factors, GABAergic (GABA+) or glutamatergic (Glut+) neurons; high efficiency: reprogramming ratio >35%.